Can see edit button, but can't edit

I'm collaborating with some fellow grad students on a project. The one who started our Prezi says she's set it so we can all edit. When I log on I do see the "edit" button on the main screen where the small Prezi thumbnails are. However, when I click on it all I get is the presentation with yellow bars on either side. I'm not seeing any of the edit tools. Can anybody tell me whats going on? I created a trial Prezi earlier in the week we can all still access and edit. So, I'm a bit mystified.